The benefits of piezoelectric actuators include high force and low power consumption while the limitations include the small displacement of the actuator. Attempts have been made to amplify the available displacement by using specialized structures. One such attempt is shown in co-owned U.S. Pat. No. 6,927,528, which discloses a piezoelectric movement amplifier arranged as a support having a rigid non-flexing portion, first and second arm portions extending rearward from the rigid portion, a pair of opposing surfaces with one opposing surface on each pivotable arm portion for movement relative to one another, and a force transfer member operably positioned between the first and second pivotable arm portions. A piezoelectric element is operably engaged between the rigid non-flexing portion and the force transfer member to drive the force transfer member in movement along a fixed path causing at least one of the first and second pivotable arm portions to pivot in response to an electrical activation of the actuator. The amplification of the piezoelectric movement is generally about a factor of five.
Another attempt is shown in U.S. Pat. No. 6,927,528, which discloses a piezoelectric movement amplifier arranged as a flexible, elliptic shell having a pair of piezoactive rod elements arranged along the large axis of the shell. Actuation of the piezoactive rods causes deflection of the shell, the result of which results in an amplification of the movement of the shell along the small axis of the shell by a factor of five over the deflection of the piezoelectric rods.